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LiChaoHui
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Delphi帮助里面的又一点内容
Callbacks
Objects can make callbacks to clients and to other transactional objects.
For example, you can have an object that creates another object.
The creating object can pass a reference of itself to the created object;
the created object can then
use this reference to call the creating object.
If you choose to use callbacks, note the following restrictions:
Calling back to the base client or another package requires access-level
security on the client. Additionally, the client must be a DCOM server.
Intervening firewalls may block calls back to the client.
Workdo
ne on the callback executes in the environment of
the object being called. It may be part of the same transaction,
a different transaction, or no transaction.
Under MTS, the creating object must call SafeRef and pass
the returned reference to the created object in order to call back to itself.
Callbacks
Objects can make callbacks to clients and to other transactional objects.
For example, you can have an object that creates another object.
The creating object can pass a reference of itself to the created object;
the created object can then
use this reference to call the creating object.
If you choose to use callbacks, note the following restrictions:
Calling back to the base client or another package requires access-level
security on the client. Additionally, the client must be a DCOM server.
Intervening firewalls may block calls back to the client.
Workdo
ne on the callback executes in the environment of
the object being called. It may be part of the same transaction,
a different transaction, or no transaction.
Under MTS, the creating object must call SafeRef and pass
the returned reference to the created object in order to call back to itself.
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